<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form method="post" action="/demo/save">
    id:<input name="id" /><br/>
    name:<input name="userName" /><br/>
    age:<input name="age" value="15"/><br/>
    <input type="submit" value="confirm"/>

</form>
</body>
</html>